Phonograph turntable mechanism



Dec. 22, 1931. H. ZABRISKIE PHONOGRAPH TURNTABLE MECHANISM Filed Dec. 22, 1928 5 Sheets-She'et gwntot Henry L. Zabrzkh'e (ozwu,

Dec. 22, 1931. H. L. ZABRISKIE PHONOGRAPH TURNTABLE MECHANISM- Filed Dec. 22, 1928 3 Sheets-Sheet 2 Zlwwntoc 17mg 1/. 245mm datum,

Dec'. 22, 1931. H. L. ZABRISKIE PHONOGRAPH TURNTABLE MECHANISM Filed Dec. 22, 1928 5 Sheets-Sheet 3 gwuewtoz [law/3L. Zabrz'sh'e' Patented Dec. 22, 1931 UNITED STATES PATENT OFFICE- A HENRY L. ZABRISKIE, OF WESTFIELD, JERSEY, ASSIGNOR TO DIEHL MANUFAC- TUBING COMPANY, OF ELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEY PHONOGRAPH TURNTABLE MECHANISM' Application filed December 22, 192B. Serial No. 327,821.

This invention relates to phonographs of the disk-record type and more particularly to .the mechanism for supporting and driving the turntable which carries the disk-record. It has for an object to provide an electrically driven turntable mechanism of simple, inexpensive and compact construction which will drive, the turntable at a-constant though controllable speed and which will notcause radio interference or introduce extraneous electrical or mechanical noises to the pick-up of the i sound reproducing system.

To the attainment of the ends in view there is provided aframe-support with cushioning means for mounting itbelow the usual topboard of a phonograph cabinet or. case. Journaled in this frame-support is the turntable-shaft at an angle and to one side of which is ournaled an elongated motor-shaft carrying the rotor of analternating current motor and a centrifugal speed-regulator of the friction-brake type. A single pair of speed-reduction gears. connect the two shafts in driving relation. A feature of the invention is the relative arrangement lengthwise of the motor-shaft, of the rotating element of the motor, the shaft bearings, the worm-drive and the speed-regulator; the rotor being disposed at one end of the shaft, the main motor-shaft bearing being next and close to the rotor, the worm-drive being next and close to the main motor bearing; the speed-regulator being next, and a steadying bearing for the motor-shaft being disposed at the extreme end of such shaft remote from the rotor. This relative arrangement of parts makes for a compact and sturdy construction which minimizes vibration and is, well adapted for installation as a turntable support and driving device for phonograph records.

' It is preferred to employ a shadedpole squirrel-cage induction motor eliminating the need for cut-outs and automatic switches,

and also eliminating allinterference'caused by commutation in motors of the type emwith its commutator and brushes.

The-gear ratio is so chosen that the turnvtable shaft maybe driven atthe standard speed of 78 R. P. h by a motor-speed sulficiently below synchronous speed to compensate for the slowing up of the motor caused by friction of the working parts including that introduced by the centrifugal speed-governor. 1

I It is also preferred to form theframe-support for the mechanism as a casting with a lubricant housing for the gears and a motorshaft bearing intersecting such housing and disposed between the rotor of the motor and theicentrifugal speed-regulator; the motorshaft being supported entirely at one end of the motor, thestator of which is received in a seat at one end of the frame-casting.

In theaccompanying drawings Fig.1 is a side elevation, partly in section, of a phono graph-record turntable mechanism embodying the invention. Fig. 2 is a reverse side elevation of the mechanism. Fig. 3 is a top plan View of the mechanism. Fig. 4 is a view of one of the pole-faces of the driving motor. Fig. 5 is a section on the line 55, Fig.1.

Fig. 6.is a section on the line 66, Fig. 1.

Fig. 7 is a section on the line 77, Fig. 5, and Fig. 8 is a motor-end view of the frame support withthe motor removed.

According to the preferred embodiment of the invention illustrated, the device comprises a supporting frame A formed as a casting and including an upper horizontal portion 1 and a lowerhorizontal portion 2 connected by spaced vertical portions 3' and 4. Secured to the arcuate seats 5, 6 in the frame-portions 1, 2 at one end of the framev is the cylindrical stator-frame 7 of an ordinary induction motor having four poles 8 embraced by the field-coils 9; the polesbeing shaded to give starting torque by the usual short-circuited copper bands 10 which embrace a portion of each pole face, asshown in Fig. 1. The field-coils 9 are connected in series relation for encrgization by the usual (SO-cycle alternating current supply; the motor thus having a synchronous speed of 1800 R. P. M.

Embraced within the stator-frame 7 is an ordinary squirrel-cage rotor 11 mounted on one end of the n'iotor-shaft 12 which is journaled horizontally in the main bearing 13 formed in the vertical portion 3 of the supportingframe and disposed in juxtaposition to the rotor 11.

Cast integral with the horizontal and vertical portions 1 and 3 of the frame is the gearhousing 1 1 in the closed bottom of which is mounted the ball step-bearing 15 for the vertically disposed turntable-shaft 16 which is disposed at one side of and in non-intersecting relation with the motor-shaft 12. The bearing ball 15 is supported by the vertical adjusting screw 17 threaded into the bottom of the gear-housing 14 and locked in adjusted position by the nut 18. The main bearing 13 opens into the cavity of the gear-housing 14, as shown in Figs. 5 and 7. The gear-housin g let is closed at its upper end by the removable plug 19 formed with a bearing 20 for the turntable-shaft 16 the plug 19 being secured in position by the set-screw 21.

Fixed to the shaft 16 within the housing 14 is a disk 22 carrying two diametrically opposed pins 23 which loosely enter the some what larger apertures 24 in the gear 25 meshing with the Worm 26 cut in the motor-shaft 12 adjacent the main bearing 13; the ratio of gearing being about 18 to 1, requiring a mo tor-speed of about 1 100 R. P. M. for the standard turntable speed of 78 R. P. M. The gear 25 is made of a suitable material having cushioning properties, minimizing the production of gear noise or vibration and the transmission of such noi e or vibration to the turn table-shaft 16. Fibrous material, such as canvas, impregnated with a phenolic condensation product or artificial resin, is found to have suitable wear-resisting and cushioning properties. The slight amount of lost motion between the gear 25 and the shaft 16 gives free play for the cushioning properties of the gear.

Slidably mounted 011 the motor-shaft 12, next to the worm 26, and farther along the shaft 12 from the rotor 11 than the worm 2G, is the centrifugally controlled speed-regulating disk 27 having a long tubular hub 28 formed adjacent the disk with a collar 29 to which is secured one end. of each of the three bow-springs 30; the other end of each of whichsprings is secured to the collar 31 fixed to the shaft 12. Ri'veted to the center of each spring 30 is a weight 32.

hen the motor is started and gathers speed, the weights 32 bow the springs 30 outwardly and draw the disk 27 along the shaft 12 into frictional working engagement with the oil-soaked felt brake-shoe 33 carried by the downwardly extending arm 34; of the bell-crank lever 3 1, 35 fulcrumed at on the frameme1nber 1; the axis of the fulcrumscrew 36 being transverse to both the motorshaft 12 and turntable-shaft 16. The other arm of the bellcrank lever extends length- 'ise of and beyond the end of the motorshaft where its return bent end 37 rests upon the collar 38 fixed to the lower end of the speed-regulating screw 39 carried by the extension at) of the fran1emember 1. The spring 11 yieldingly maintains the belicrank lever-arm in enga ement with the collar 38. It will be understood that the working speed of the motor is governed by the posi tion of adjustment of the stationary brakeshoe 33, which produces a drag upon the motor-shaft suiiicient to pull the speed of the turntableshaft down to the desired value.

A speeda'egulator of the type described, while quite satisfactory as to its speedgov erning characteristics, is ditlicult to balance so closely that it will not vibrate its supporting shaft. To steady the shaft 12 for the support of the speed-governor, there is provided at the end of such shaft remote from the motor, a bearing 12 which, together with the main bearing, supports the motor-shaft at both ends of the speed-governor and makes for quiet running and smooth operation. It will be observed that the speed governing and adjusting mechanism is carried in its entirety by the supporting frame A.

Fixed to the turntable shaft 16 above the frame-member l is a turntable supporting collar 13 having a conical upper face s 1 upon which a felt washer 15 is pressed by the mat ing conical surface ill at the lower end of the hub 4-7 of the turntable 18 which supports the phonograph record 19. The felt washer 15 and mating conical faces A, 46, constitute a friction-clutch having a sufiicicnt grip to drive the record 19 under the usual pick-up needle (not shown). This friction-clutch prevents the gears from being damaged in case the turntable forcibly turnbd bv hand or held from turning by a careless operator. It also prevents the transmission of motor noise or vibration to the turntable.

The entire device is suspended from the usual top-board cf the cabinet or carrying case by means of three screws 51 which are tapped into the frame-member 1. Top cushioning springs are interposed between the board 50 and the screw-head washers and bottom cushioning springs 53 are interposed between the board 50 and the frame member 1. These cushioning springs absorb any remanent vibration and prevent the transmission of hum or vibration to the supporting cabinet or carrying case.

Lubrication of the gears 25, 2G and the lower bearing for the shaft 16 is taken care of Lad by packing the gear-housing 14 with a suita le grease. A felt-packed duct 54:, Fig. 7, along the bearing 13, lubricates the latter from the lubricant supply in the housing 14. The top-bearing 20 for the shaft 16 is lubricated through the wick 55 leading from the oiltube 56. A similar oil-tube 57 and wick 58 are provided for lubrication of the endbearing 42. i

The shaft-aperture in the bearing 13 is preferably slightly enlarged at 13 where it embraces the worm 26; the enlargement being insuificient to permit escape of the" grease used as a gear lubricant. The gears, being totally enclosed, will run for a long time in clean grease, free from grit and dirt.

Having thus set forth the nature of the invention, what I claim herein is l. A phonograph-record turntable mecha nism comprising a supporting frame formed with spaced and alined motor-shaft bearings, a motor stator-frame carried by said supporting frame at the end of one of said bearings remote from the other bearing, a rotor embraced by said stator-frame, a motor-shaft carrying said rotor and journaled in said bearings, a centrifugal brake-member mounted on said motor-shaft between said bearings, and a turntable-shaft journaled in said supporting fram and geared to said motorshaft. 7

2. A phonograph-record turntablemechanism comprising a supporting frame, a drivinotor including a motor-shaftjournaled horizontally in said frame, a turntable-shaft jo-urnaled vertically in said frame, speed-reduction gearing connecting said shafts, a centrifugally operated brake-disk mounted on and movable lengthwise of the motor-shaft, a bell-crank lever fulcrumed on a horizontal axis disposed above and transverse to the motor-shaft, one arm of the bell-crank lever extending downwardly and the other arm extending in the direction of and beyond the end of the motor-shaft, a brake-shoe carried by the downwardly extending arm of the bell-crank lever in position to be engaged by the brake-disk, and a vertically disposed regulating screw carried by said frame and connected at its lower end to the horizontally extending arm of the bell-crank lever.

3. A phonograplrrecord turntable mechanism comprising a supporting frame, an electric motor including a stator carried by said frame at one end of the latter, arotorshaft, a rotor at one end of the rotor-shaft, a main rotor bearing in said frame next to the rotor,

a worm on the rotor-shaft next to said bearing, a centrifugal brake element on the rotorshaft next to said worm, a second rotor-shaft bearing in said frame next to said centrifugal brake element for steadying the end of said shaft adj acent said centrifugal brake element, a turntable-shaft journaled in said frame transversely and in non-intersecting V relation with the motor-shaft,and a gear on nected by spaced webs in spaced relation, motor shaft bearings in said spaced webs,

complementary motor seats in said upper and lower'portions of the frame at one end of the frame structure, an electric motor mounted in said complementary seats at the end of the frame and having a shaft journalled in the bearings in the spaced webs, a governor on said shaft in the space between the webs and a turn-table spindle driven from said motor shaft.

5. Inphonograph apparatus, a supporting frame having a horizontally extending substantially circular motor seat at one end and a motor shaft bearing substantially concentric to said seat, an electric motor having a stator engaged in said seat and a cooperating rotor provided with a shaft engaged in the bearing, a gear element carried by said motor shaft and a vertical spindle journalled on the frame and having a gear element in engagement with the gear element on the shaft.

6. In phonograph apparatus, a supporting frame having a horizontally extending substantially circular motor seat at one end and a motor shaft bearing substantially concentric to said seat, an electric motor having a stator engaged in said seat and a cooperating rotor provided with a shaft engaged in the bearing, a gear element carried by said motor shaft, a vertical spindle journalled on the frame and having a gear element in engagement with the gear element on the shaft and horizontally extending screws on the frame and exerting an endwise thrust on the motor stator to removably secure the latter in the end seat aforesaid.

7. In phonograph apparatus, a supporting frame having a horizontally extending motor shaft bearing and a substantially circular motor seat at one end of the frame substantially concentric to said motor shaft bearing, an electric motor applicable endwise to said motor seat and bearing and comprising an annular stator engageable horizontally with the substantially circular motor seat and a cooperating rotor having a shaft extending from one side thereof and engageable endwise in the shaft bearing, screw means for detachably securing the stator to the motor seat, adjustable means for releasably securing the rotor shaft against endwise displacement in the bearing, a spindle journalled for vertical rotation on the supporting frame and drive gearing from the rotor shaft to said vertical spindle.

8. In phonograph apparatus, the combination of a supporting frame, a spindle journalled on said frame and provided with a worm gear and an electric induction motor mounted on said frame and comprising an annular stator detaohably mounted on the frame and a cooperating rotor detachably journalled in the frame, said rotor being removable from the frame independently of the stator, means by which said stator is thus detachably secured to the frame, means for detachably journalling the rotor in the frame and for enabling said rotor to be removed from the frame independently of the stator, a vertical spindle journalled on the "frame and re1n0 .abl" i1dependently of both stator and rotor and drive gearing between the rotor shaft and spindle.

In testimony whereof, I have signed my name to this specification.

HENRY L. ZABRISKIE. 

